Numerical Slug Flow Model of Curved Pipes with Experimental Validation.

The research for gas-liquid two-phase flow is very important for flow assurance and flow stability of chemical transportation. In terms of transportation pipelines, the curved section is a very significant part. Therefore, the present work proposes a transient slug flow model for the curve pipes, and we conducted some experiments to validate it. This slug flow model is a four-equation model that contains mass and momentum balances with the closure relations. The normal two-dimensional rectangular coordinate system is simplified to the one-dimensional polar coordinate system, which will make the simulation faster and easier. The common flow parameters, such as the pressure profile along the pipeline, real-time pressure, and liquid holdup, are calculated in this model. Three groups of experiments with three different pipe curvatures were carried out to validate this model; the experiments were under the same conditions as those of the model calculations. The transient pressure and liquid holdup were measured at the middle of the curved pipe. The experimental data are compared to the calculated results, and there are error analyses of pressure and liquid holdup that are made to review the model's performance. The analyses show that a large proportion of the pressure errors is within 10%, and most of the liquid holdup errors are within 0.1. The comparisons between the model and experiments show good agreement.